02-persistent-sessions

02: Persistent Sessions

Key Insight: JSONL is the simplest crash-safe persistence format.

What's New vs 01

• Per-user session files in ./sessions/{user_id}.jsonl
• Multi-turn conversation memory that survives restarts
• Append-only persistence (crash-safe — partial writes don't corrupt)

What You'll Learn

• How to persist conversation history to disk
• Why JSONL (one JSON object per line) is ideal for append-only logs
• How per-user isolation works with file-based sessions

Prerequisites

• Completed module 01
• Anthropic API key and Telegram bot token in .env

How to Run

make 02-persistent-sessions
# or
uv run python 02-persistent-sessions/bot.py

Directory Structure

02-persistent-sessions/
    bot.py
    sessions/           <- Created automatically
        12345.jsonl     <- One file per Telegram user ID
        67890.jsonl

What to Observe

1. Memory persists — Tell the bot your name, then ask "What's my name?" — it remembers
2. Survives restarts — Stop the bot (Ctrl+C), restart it, ask again — still remembers
3. Per-user isolation — Each Telegram user gets their own session file

Files

File	Lines	Description
bot.py	~80 lines	Bot with JSONL session persistence

Next Module

Ready for personality? -> 03: Personality & Soul